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Purpose: To examine the influence of fluid intake on heat acclimation and the subsequent effects on exercise performance following acute hypohydration.
Methods: Participants were randomly assigned to 1 of 2 groups, either able to consume water ad libitum (n = 10; age 23 [3] y, height 1.81 [0.09] m, body mass 87 [13] kg; HAW) or not allowed fluid (n = 10; age 26 [5] y, height 1.76 [0.05] m, body mass 79 [10] kg; HANW) throughout 12 × 1.5-h passive heat-acclimation sessions. Experimental trials were completed on 2 occasions before (2 baseline trials) and 1 following the heat-acclimation sessions. These sessions involved 3 h of passive heating (45°C, 38% relative humidity) to induce hypohydration followed by 3 h of ad libitum food and fluid intake after which participants performed a repeat sled-push test to assess physical performance. Urine and blood samples were collected before, immediately, and 3 h following hypohydration to assess hydration status. Mood was also assessed at the same time points.
Results: No meaningful differences in physiological or performance variables were observed between HANW and HAW at any time point. Using pooled data, mean sprint speed was significantly (P < .001) faster following heat acclimation (4.6 [0.7] s compared with 5.1 [0.8] s). Furthermore, heat acclimation appeared to improve mood following hypohydration.
Conclusions: Results suggest that passive heat-acclimation protocols may be effective at improving short-duration repeat-effort performance following acute hypohydration.
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http://dx.doi.org/10.1123/ijspp.2019-0092 | DOI Listing |
Mar Life Sci Technol
August 2025
School of Life Sciences, State Key Laboratory of Microbial Technology, Shandong University, Qingdao, 266237 China.
Unlabelled: Mongolian gerbils had high ability to endure both high and cold temperatures. To study the mechanism of high ability for thermal adaptation, gerbils were acclimated to high temperature (30 °C) for 8 weeks, and were measured for metabolic features, body composition as well as mitochondrial content and activities. Lipidomic techniques were used to measure changes in mitochondrial membrane, including potential mitochondrial membrane remodeling during acute thermoregulation in gerbils.
View Article and Find Full Text PDFEvol Med Public Health
July 2025
Department of Evolutionary Anthropology, Duke University, Durham, NC, USA.
Background And Objectives: Water is essential for proper physiological function. As temperatures increase, populations may struggle to meet water needs despite adaptations or acclimation; chronic dehydration can cause kidney damage. We evaluate how daily water requirements are associated with ambient temperature (ambT), wet bulb globe temperature (WBGT), urine specific gravity (USG; marker of hydration status), and albumin:creatinine ratio (ACR; kidney function biomarker) among Daasanach pastoralists living in a hot, dry northern Kenyan climate.
View Article and Find Full Text PDFPhysiol Plant
September 2025
Centre of Molecular and Environmental Biology (CBMA), Department of Biology, School of Sciences of the University of Minho, Braga, Portugal.
The Mediterranean Basin, a hotspot for tomato production, is one of the most vulnerable areas to climate change, where rising temperatures and increasing soil and water salinization represent major threats to agricultural sustainability. Thus, to understand the molecular mechanisms behind plant responses to this stress combination, an RNA-Seq analysis was conducted on roots and shoots of tomato plants exposed to salt (100 mM NaCl) and/or heat (42°C, 4 h each day) stress for 21 days. The analysis identified over 8000 differentially expressed genes (DEGs) under combined stress conditions, with 1716 DEGs in roots and 2665 in shoots being exclusively modulated in response to this specific stress condition.
View Article and Find Full Text PDFJ Fish Biol
September 2025
Department of Biological Sciences, University of New Brunswick - Saint John, Saint John, New Brunswick, Canada.
Many Arctic fishes experience prolonged periods of extreme cold and large thermal variation over both rapid and seasonal time scales which challenge critical physiological functions. In the central Canadian Arctic, we caught wild adult lake trout (Salvelinus namaycush) acclimatized to winter and summer temperatures to determine the extent to which they seasonally adjust cardiac thermal performance and adrenergic control. We assessed the intrinsic and maximum heart rate (f and f) of anaesthetised fish through cholinergic blockade and either adrenergic blockade (f) or stimulation (f) during acute warming.
View Article and Find Full Text PDFJ Appl Physiol (1985)
September 2025
Thermal and Mountain Medicine Division, U.S. Army Research Institute of Environmental Medicine, Natick, MA, USA.
Individuals who work in the heat, such as military personnel and athletes, are often required to rapidly transition from temperate or cooler climates to hot environments. Thus, acclimation strategies are needed for individuals lacking access to hot weather. We sought to develop and validate a practical exercise with overdressing protocol for heat acclimation.
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